Submission #90477

#	Time	Username	Problem	Language	Result	Execution time	Memory
90477		radoslav11	Bitaro’s Party (JOI18_bitaro)	C++14	100 / 100	1451 ms	400676 KiB

bitaro

#include <bits/stdc++.h>
#define endl '\n'

#define SZ(x) ((int)x.size())
#define pb push_back

using namespace std;
template<class T, class T2> inline void chkmax(T &x, const T2 &y) { if(x < y) x = y; }
template<class T, class T2> inline void chkmin(T &x, const T2 &y) { if(x > y) x = y; }
const int MAXN = (int)1e5 + 17 + 42;
const int B = 200;

int n, m, q;
vector<int> adj[MAXN];

void read()
{
	cin >> n >> m >> q;
	for(int i = 0; i < m; i++)
	{
		int u, v;
		cin >> u >> v;
		adj[v].push_back(u);
	}
}

bool ok[MAXN];

int _dp[MAXN];
int Tm_vis[MAXN], cnt_t;
int TMS = 0;

vector<pair<int, int> > dp[MAXN];

int rec(int u)
{
	if(Tm_vis[u] >= cnt_t) return _dp[u];
	Tm_vis[u] = cnt_t;
	if(ok[u]) _dp[u] = 0;
	else _dp[u] = -1e9;

	for(int v: adj[u])
		chkmax(_dp[u], rec(v) + 1);

	return _dp[u];
}

int solve_brute(int u, vector<int> blocked)
{
	for(int x: blocked) ok[x] = 0;
	cnt_t++;
	int ans = rec(u);
	for(int x: blocked) ok[x] = 1;
	return ans < 0 ? -1 : ans;
}

bool same[MAXN];

bool cmp(pair<int, int> a, pair<int, int> b) { return a.second > b.second; }

int USED[MAXN];

vector<pair<int, int> > merge(vector<pair<int, int> > a, vector<pair<int, int> > b)
{
	for(auto &it: b) it.second++;

	int po_b = 0;
	vector<pair<int, int> > ret;
	for(auto it: a) 
	{
		while(po_b < SZ(b) && b[po_b].second > it.second)
		{
			if(USED[b[po_b].first] != -1) { po_b++; continue; }
			else
			{
				USED[b[po_b].first] = 1;
				ret.pb(b[po_b]);
				po_b++;
			}
		}

		if(USED[it.first] != -1) continue;
		USED[it.first] = 1;
		ret.pb(it);
	}

	while(po_b < SZ(b))
	{
		if(USED[b[po_b].first] != -1) { po_b++; continue; }
		else
		{
			USED[b[po_b].first] = 1;
			ret.pb(b[po_b]);
			po_b++;
		}
	}

	for(auto it: ret) USED[it.first] = -1;
	while(SZ(ret) > B) ret.pop_back();
	return ret;
}

void solve()
{
	memset(USED, -1, sizeof(USED));
	for(int i = 1; i <= n; i++) ok[i] = 1;

	for(int u = 1; u <= n; u++)
	{
		dp[u].push_back({u, 0});
		for(auto v: adj[u])
			dp[u] = merge(dp[u], dp[v]);
	}

	while(q--)
	{
		int st, sz;
		vector<int> li;

		cin >> st >> sz;
		for(int i = 0; i < sz; i++)
		{
			int x;
			cin >> x;
			li.push_back(x);
		}

		vector<int> initial_li = li;

		if(li.size() >= B)
		{
			cout << solve_brute(st, li) << endl;
			continue;
		}

		for(auto it: li) same[it] = 1;

		int answer = 0;
		for(auto it: dp[st])
			if(!same[it.first])
				chkmax(answer, it.second);

		for(auto it: li) same[it] = 0;

		if(answer < 0) answer = -1;
		if(answer == 0)
		{
			for(auto it: initial_li)
				if(it == st) answer = -1;
		}

		cout << answer << endl;
	}
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	read();
	solve();
	return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 86 / 86